<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        /* 伪元素 */
        div::first-letter{
            font-size: 20px;
        }

        div::first-line{
            /* font-size: 30px; */
            background: yellow;
        }

        div::before{
            content: "aaaa";
        }
        div::after{
            content: "bbbb";
        }
    </style>
</head>
<body>
    <div>Lorem ipsum dolor sit amet consectetur adipisicing elit. Eum, dolorum aut ipsa accusantium veritatis impedit? Id, facilis aut autem sapiente eos ad vel dolores error voluptatum minima enim accusamus ea?</div>
</body>
</html>